Adjustable jack



FIG. 1 is a first perspective view of an adjustable jack showing my new design;

FIG. 2 is a second perspective view thereof;

FIG. 3 is a front view of FIG. 1 ;

FIG. 4 is a rear view of FIG. 1 ;

FIG. 5 is a left side view of FIG. 1 ;

FIG. 6 is a right side view of FIG. 1 ;

FIG. 7 is a top plan view of FIG. 1 ; and,

FIG. 8 is a bottom plan view of FIG. 1 .

The broken lines in the drawings depict portions of the adjustable jack that form no part of the claimed design. 

CLAIM The ornamental design for an adjustable jack, as shown and described. 